It varies, but I keep carbs dry carbs. So no taters or carbs that have a lot it water in them. With my digestive issues, things like rice cakes, chex, gluten free cereal bars, raw honey... I don't eat high protein on show day as I feel like the more protein I eat the harder it is to hit my abs. If I know I an super dry and need to fill out and a little water will add fullness, I go for sushi. That is really my go-to. Rice doesn't bloat me and doesn't make me hold water, so I like to use lots of rice. I'll add honey with some almond butter to rice cakes and eat that as it gets closer to stepping on stage. I also make adjustments with sodium if I have carbs and can't get a pump, I add in 500mg sea salt. Then I hit done poses and if still no pump, sip a little water. Still no pump, a little more sea salt, almond butter and honey.
If you still can't get a pump after that I opt to "shit load" if I was dry, which in my case I make sure I am dry as it's one mess thing to toggle with and optimize on show day.
Basically, there is no set in stone practice on show day for. It evolves with how I look and feel